The critical procedures in this unit are measurements of airway resistance, breathing frequency, and tidal volume, and administering the test for airway hyperresponsiveness for specific allergen, HDMA and nonspecific (methacholine, phenyl biquanine) challenges. These data will be expressed as CDA 200 or EC 200 Raw, the concentration or dose of challenge needed to double airway resistance. Raw will be measured using Transfer Impedance which involves an established model of airway mechanics to predict airway resistance from wave forms generated by acoustical speakers. The wave forms are sensitive to changes in airway caliber and are determined from the pressure recordings in the pleythsmograph box and the airway flow recorded in pneumotchograph connected to the monkey by a face mask or endotracheal tube.